Judges at the Court of Session in Edinburgh have ruled the case against the Scottish Government's policy should be referred to the Court of Justice of the European Union.
The legal challenge was brought by the Scotch Whisky Association (SWA), which has argued minimum pricing legislation breaches European law.
Doctors and alcohol awareness campaigners expressed concern that any delay before the European court rules on the case would mean a continued impact on the health of the nation.
Dr Evelyn Gillan, chief executive of Alcohol Focus Scotland, said: "If the appeal judges feel that clarification is needed on technical matters then we can only hope that this process does not drag on.
"Every week that minimum pricing is delayed, another 20 Scots lose their lives because of alcohol. It is frustrating to see a policy that has been agreed through the democratic process being held up by big business, who care more about protecting profits than the health and wellbeing of the people of Scotland."
Dr Peter Rice, chairman of Scottish Health Action on Alcohol Problems, said: "We have had detailed consideration of this measure over an extended period. Minimum pricing should have been implemented over a year ago and further delay is bad for Scotland's health and wellbeing."
The Alcohol (Minimum Pricing) (Scotland) Act 2012 was passed by Holyrood in June 2012, paving the way for the introduction of a preferred minimum price of 50p per unit, but implementation has been delayed by legal challenges.
The SWA's legal bid was rejected by Lord Doherty in May 2013 following an Outer House hearing in the Court of Session in January 2013. An appeal to the court's Inner House, heard by Lord Eassie, Lord Menzies and Lord Brodie, took place in February.
The appeal focused on determining the aim of minimum unit pricing, whether this aim could be achieved using alcohol excise duties and whether the policy was proportionate to protect public health and therefore justifiable under the Treaty on the Functioning of the EU (TFEU).
In a written opinion published yesterday, Lord Eassie wrote that "the present proceedings raise aspects of those tests and of the role of the national court which are not clearly established".
SWA chief executive David Frost said: "We are pleased that the Court of Session in Edinburgh is referring the minimum unit pricing (MUP) case to the Court of Justice of the European Union. From the outset we said that we believed MUP was contrary to European Union law and that it was likely in the end to go to the European Court.
"We also believe MUP would be ineffective in tackling alcohol misuse and would damage the Scotch whisky industry in the UK and overseas."
Health Secretary Alex Neil welcomed the referral from the court and stressed it was right that this "precedent-setting case" was considered by the highest authority on EU law.
He said: "Scotland is leading the way in Europe. We are confident of our case and look forward to presenting it in the European Court of Justice. While it is regrettable that this means we will not be able to implement minimum unit pricing sooner, we will continue our ongoing and productive dialogue with EU officials."